Coastal and marine areas: the Polar Regions

THE ARCTIC

The global ocean circulation

When warm, salty North Atlantic water reaches
the cold Arctic, it becomes denser as it cools, and therefore sinks
to deeper layers of the ocean. This process of forming deep water
is slow but takes place over a huge area. Every winter, several
million cubic kilometres of water sink to deeper layers, which move
water slowly south along the bottom of the Atlantic Ocean

Source: AMAP 1997

The Arctic marine environment covers approximately
20 million km2 and includes the Arctic Ocean and several adjacent
water bodies. Nearly half of the ocean floor is continental shelf, the
highest percentage among all oceans. Movements of Arctic waters play a
significant role in the global ocean regime (AMAP 1997), and in regulating
the global climate (see figure).

The Arctic marine environment is rich in fish biodiversity and abundance.
The commercial fisheries of the Barents and the Bering systems are among
the most productive in the world (Kelleher, Bleakly and Wells 1995), with
the Bering Sea accounting for 2-5 per cent of the world's fisheries catches
(CAFF 2001, Bernes 1996). Resident and migratory marine mammals include
whales, seals and sea lions. The polar bear is also often classified as
a marine mammal because it frequents sea ice in search of prey. Many of
the indigenous communities of the Arctic have traditionally depended on
these marine resources for their livelihood. Other natural resources include
vast oil and gas reserves along the continental shelves as well as important
mineral deposits. However, there are growing concerns about the negative
impacts of development activities on the ecology of the Arctic especially
in ice-prone areas and critical habitats.